It is known to use an artery graft represented by internal thoracic artery, gastroepiploic artery and radial artery or a vein graft represented by great saphenous vein as a bypass vessel in performing vascular bypass grafting at the heart (coronary artery bypass grafting: CABG). Besides, at present, it has been reported that artery grafts (particularly, internal thoracic artery) offer higher long-term patency rates than vein grafts. Thus, vein grafts are commonly said to be poor in long-term patency rate. In recent years, however, it has been reported that the long-term patency rate concerning a vein graft is enhanced when the vein graft is harvested in the state of being covered with the surrounding tissue (for example, fat, connective tissue, tissue between a skin layer and a muscle layer, tissue between a skin layer and an interosseous membrane, branch vessels, etc.) and is used as a bypass vessel while remaining covered with the tissue. U.S. Application Publication No. 2006/0276815 describes an example of a device by which a vein graft can be harvested in the state of being covered with the surrounding tissue.
In using the device disclosed in U.S. Application Publication No. 2006/0276815, a guide wire (support member 50) is inserted into a blood vessel to be harvested as a bypass vessel, and a tubular member (portion 40) is pushed forward while guiding it with the guide wire, whereby the blood vessel can be harvested in the state of being covered with the surrounding tissue. The device disclosed in US 2006/0276815, however, has drawbacks in that the guide wire may damage the internal wall of the blood vessel being harvested and that the workability in blood vessel harvesting (blood vessel dissection) is poor.